DE-A-39 18 824 and U.S. Pat. No. 5,105,525 show a flatiron sole which has an especially scratch-resistant, readily slidable and easy-to-clean surface. The flatiron sole is coated with a nickel hard alloy and is ground and polished by a drag finishing method.
A method of producing a coating on a gas turbine blade is described in U.S. Pat. No. 4,321,310. The gas turbine blade has a parent body made of a cobalt-base or nickel-base superalloy. An adhesive mediator layer of the MCrAlY type is applied to this parent material. In this case, M, for example, designates a combination of the metals nickel and cobalt. Cr stands for chrome and Al stands for aluminum, and Y stands for yttrium. A ceramic layer of zirconium oxide which has grown in a columnar manner is applied to this adhesive mediator layer, the columns being oriented essentially perpendicularly to the surface of the parent body. Before the zirconium oxide layer, serving as heat-insulating layer, is applied to the adhesive mediator layer, the adhesive mediator layer is polished until a surface roughness of about 1 μm appears.
U.S. Pat. No. 5,683,825 likewise discloses a method of applying a heat-insulating layer to a component of a gas turbine. An NiCrAlY adhesive mediator layer is applied to the parent body by low-pressure plasma spraying. The surface of the adhesive mediator layer is polished, so that it has a surface roughness of about 2 μm.
By way of a vapor deposition process (PVD, physical vapor deposition), a ceramic heat-insulating layer with yttrium-stabilized zirconium oxide is applied to the adhesive mediator layer polished in such a way. In this case, the heat-insulating layer is preferably applied with the “electron-beam PVD process.” The heat-insulating layer may also be applied by way of plasma spraying.
The application of a heat-insulating layer to an adhesive mediator layer of a component of a gas turbine is likewise described in U.S. Pat. No. 5,498,484. The average surface roughness of the adhesive mediator layer is specified as at least above 10 μm.
U.S. Pat. No. 5,645,893 relates to a coated component having a parent body made of a superalloy and having an adhesive mediator layer and a heat-insulating layer. The adhesive mediator layer has a platinum aluminide and an adjoining thin oxide layer. The thin oxide layer has aluminum oxide. Adjoining this oxide layer is the heat-insulating layer, which is applied by way of the electron-beam PVD process. In this case, zirconium oxide stabilized with yttrium is applied to the adhesive mediator layer. Before the adhesive mediator layer is applied, the surface of the parent body is cleaned by way of a coarse sand blasting process. Aluminum oxide sand is used in this case in order to remove material from the parent body.